According to the prior art an installation is known for production of a rubber mass comprising a tank for mixing of the mass.
The tank comprises an opening for loading of the tank, an opening for discharge of the rubber mass, and a door for shutting of the discharge opening. This door is mobile in rotation between a position of shutting of the discharge opening and a position of release of this opening.
The tank also comprises rotary mechanical mixing means such as mixing rotors which are fitted such as to rotate around axes which are substantially parallel to the axis of the door. The tank also comprises a surface for closure of the tank, which is designed to co-operate with a complementary surface for closure of the door in the shutting position of the door.
When the door is opened, a space is created between the complementary closure surfaces. This space forms an aperture for extrusion of the rubber during mixing. Under the effect of the pressure which exists inside the tank, mixed rubber is extruded via this aperture, and a layer of rubber adheres to the complementary closure surfaces.
When the door is in its position of release, the rubber mass drops from the tank. In order to mix a new rubber mass, the door is displaced once more from its position of release into its shutting position.
However, after several cycles of displacement of the door between its positions of release and shutting, a cake of rubber formed by different layers of rubber extruded under pressure accumulates on the complementary closure surfaces, and prevents correct closure of the door.
An operator must then clean these surfaces manually in order to detach the cake of rubber which is adhering to these surfaces. This cleaning is time-consuming, and needs the installation to be stopped throughout the duration of the cleaning, which disrupts the rates of production of rubber. In addition, the presence of an operator involves safety measures consisting of deactivating the installation temporarily, thus disrupting the rates of production further.